Means for feathering rubber stock

ABSTRACT

Apparatus for skiving edge portions of sheet stock is disclosed. The apparatus includes a table having a surface adapted to support sheet stock so that an edge of the stock is in coplanar relationship with an edge of the table. A pair of rollers are mounted over the table and those rollers drive an endless abrasive belt. The belt has a flat reach extending at an acute angle with respect to the plane of the table and at least a portion of the flat reach overlies and is intersected by a plane normal to the table and passing through the table edge.

United States Patent 1 Wiltshire 1 Dec.2, 1975 I MEANS FOR FEATHERINGRUBBER STOCK [75] Inventor: Arthur J. Wiltshire, Richmond FOREIGNPATENTS OR APPLICATIONS 1,835 8/1854 United Kingdom 51/147 PrimaryExaminer-Al Lawrence Smith Assistant Examiner-Nicholas P. GodiciAttorney, Agent, or FirmMcNenny, Farrington, Pearne & Gordon [5 7]ABSTRACT Apparatus for skiving edge portions of sheet stock isdisclosed. The apparatus includes a table having a surface adapted tosupport sheet stockso that an edge of the stock is in coplanarrelationship with an edge of the table. A pair of rollers are mountedover the table and those rollers drive an endless abrasive belt. Thebelt has a flat reach extending at an acute angle with respect to theplane of the table and at least a portion of the flat reach overlies andis intersected by a plane normal to the table and passing through thetable edge.

4 Claims, 3 Drawing Figures U.S. Patent Dec. 2, 1975 Sheet 1 of23,922,820

U.S. Patent Dec. 2, 1975 Sheet 2 of2 3,922,820

MEANS FOR FEATHERING RUBBER STOCK BACKGROUND OF THE INVENTION Thisinvention relates to skiving apparatus, and more particularly toapparatus for providing a taper along the edges of sheet stock so thatthe tapered edges may be overlapped and bonded to provide a seam havinga thickness corresponding to the thickness of the sheet stock. Deviceswhich are intended to provide skived or feathered edges on sheet stockgenerally comprise a table having a surface adapted to support the stockand an abrasive belt trained between the rollers. A portion of the beltwhich is wrapped about one of the rollers is brought into engagementwith the edge of the sheet and the roller is then moved along the edgeof the sheet from one end thereof to the opposite end. Although thisarrangement provides the sheet with a tapered edge, it is not a flattaper which would accurately mate with a corresponding flat taperprovided at the opposite edge of the sheet, since the curvature of theroller provides a corresponding curvature to the taper.

While in most applications such a discontinuity may be tolerated, thereare situations where precise mating must obtain 'to provide a uniformseam. For example, precise seams are required in forming expandable bagswhich are employedin forming the interior surface of hollow,fiber-reinforced articles. Such molding tech niques are commonlyreferred to as bag molding techniques and are set forth in US. Pat. No.Re. 25,241, to D. W. Randolph. According to the techniques described inthat patent, hollow, cylindrical, fiber-reinforced plastic tanks havebeen pressure-molded by laying up fiber matting in a rigid mold casingin the approximate form of the desired article. A complete fiber formmay include preformed, matted fiber end wall caps which telescope into alaid up, cylindrical sidewall portion.

An expandable bag or envelope which will define the interior shape ofthe finished article is positioned within the laid up form in the mold.Rigid casing caps which shape the end walls of the final article areclamped to the ends of the rigid mold casing to enclose the fiber matform. With the fiber matting and mold thus assembled, the fiber mattingis placed under a suitable moderate pressure by expanding the bag tohold it in place against the mold. The fiber matting is then permeatedwith a thermosetting resin or the like. The bag, besides defining theinterior surface of the molded tank and determining the properfiber-to-resin ratio, compresses the fiber lay-up in such a manner as toavoid migration of fibers with resin flow and resulting destruction ofthe lay-up. Such bags have been formed by overlapping opposite edgeportions of a sheet of neoprene and joining those edge portions by asuitable neoprene cement which sets upon the application of heat. Aftera hollow neoprene tube has been formed in this manner, a sheet ofneoprene is applied to one end of the tube and a sec ond end piece isapplied to the other end together with an air fitting.

While such bags have been employed successfully in the manufacture offiber-reinforced plastic pressure vessels, they have certain defects.One such defect is the fact that the longitudinal, non-feathered lapseam forms a longitudinal ridge in the sidewall of the molded pressurevessel and this ridge provides a structural discontinuity in a zone ofabnormal stress concentration when the tank is pressurized.

SUMMARY OF THE INVENTION This invention overcomes these prior artproblems by providing apparatus for skiving opposite edges of neoprenesheet stock so that those edges may be accurately mated to produce aseam which does not vary in thickness as compared to the remainder ofthe stock.

The apparatus comprises a flat table having a surface adapted to supportsheet stock and a vacuum gripping means associated with the table toretain an edge of the stock in coplanar relationship with an edge of thetable. An endless abrasive belt is mounted between a drive roller and anidler roller to provide a flat reach which extends at an acute anglewith respect to the plane of the table. At least a portion of the flatreach overlies and is intersected by a plane normal to the table andpassing through the table edge. This arrangement ensures that the sheetstock will be skived to produce a flat tapered edge rather than a curvedtapered edge. A carriage and guide rod arrangement guides the rollersand their associated belt in a path along the edge which maintains theportion of the flat reach in its overlying relationship. After makingone rough cut pass along the edge of the sheet stock, the direction ofthe carriage is reversed and the belt and roller assembly is lowered toprovide a finish pass.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, perspectiveview of a skiving arrangement according to this invention;

FIG. 2 is a fragmentary, cross sectional view, the plane of the sectionbeing indicated by the line 22 in FIG. 1; and

FIG. 3 is a fragmentary, cross sectional view, the plane of the sectionbeing indicated by the line 3-3 in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings,there is illustrated a skiving machine 10. The machine 10 includes aflat table 11 adapted to support sheet stock such as the illustratedsheet of neoprene 13. An edge 14 of the sheet 13 is retained in coplanarrelationship with an edge 15 of the table 11 by drawing a vacuum througha multiplicity of perforations 16 in the table 11.

The edge 14 is tapered or skived by an endless abrasive belt 17 mountedbetween a drive roller 18 and an idler roller 19. The belt 17 has a flatreach 20 extending at an acute angle with respect to the plane of thetable and, as may be seen in the drawings, at least a portion of thatflat reach overlies and is intersected by a plane normal to the tableand passing through the edge 15. That portion of the reach 20 is backedby a flat plate 20a.

The roller 19 is rotatably mounted on a support arm 21, which in turn ismounted on the end of a beam 22. The beam 22 is rigidly associated withan arm 23 of a support 24. As may be seen in FIG. 1, the drive roller 18is carried by an axle 25, which extends through the arm 23 and is drivenby a motor 26 through a first pulley 27, a belt 28, and a second pulley29 fixed to the axle 25. The bracket 24 has a central hub portion 30which is slidably and rotatably mounted on a guide rail 31 extendingacross the table 11 and parallel to the edge 15.

Means are provided to drive the support 24 along the guide rail 31 sothat the portion 20 of the belt 17 traverses the edge of the sheet 13.Such means comprise a 3 shaft 32 which is provided with acme threads andwhich is driven by a motor 33 through suitable gears and clutchesprovided in a casing 34. The acme thread is engaged by a plurality offingers 35 which are provided on a plate 36 fixed to the hub portion 30.

In order to support the roller 19 and its support arm 21 relative to thefront edge of the table, and to maintain a predetermined skivin g anglefor the belt 17, there is provided a roller assembly 37. The assembly 37has a base member 38 which is fixed to the support arm 21 by an arm 39.A shaft 40 projects from the base member 38 and rotatably carries aroller 41. The roller 41 has a relatively small diameter end portion 42and a larger diameter intermediate portion 43. As the belt 17 and itsassociated rollers 18 and 19 are driven from right to left, as viewed inFIG. 1, a rough initial taper is effected as the portion 43 rides alonga shelf 44. When the belt 17 reaches the end of its travel past the leftside edge of the sheet 13, a limit switch 45 is engaged by a button 46on the portion 38. When the limit switch 45 is contacted, the clutchwhich drives the threaded shaft 32 is reversed to reverse the directionof rotation of the shaft 32 to drive the belt 17 to the right. The limitswitch 45 also energizes a solenoid 47 so that a rod 48 of the solenoiddrives the roller 41 to the left and to the position illustrated in FIG.3. The roller 41 is retained in the position illustrated by aspring-loaded ball detent 49, which is received within an annular groove50 in the rod 40.

Since the portion 42 has a smaller diameter than the portion 43, thebelt 17 is lowered to provide a fine finish cut during traversal of thebelt to the right as viewed in FIG. 1. After the belt 17 traverses thefront edge of the sheet 13, the roller 41 rides upwardly along a camsurface 51 to move the belt 17 upwardly away from the table. Another camplate 52 has fingers 53 which receive and straddle the shaft 40 andwhich push the roller 41 inwardly toward the table so that the detent 49engages an annular groove 54 in the shaft 40. In this manner, the roller41 is in position for a rough cut on another sheet. Further movement ofthe belt 17 to the right causes a button 55 on the base portion 38 toengage a limit switch 56. When the limit switch 56 is engaged, themotors 26 and 33 are shut off to stop the shaft and the belt 17. Thesheet 13 is then turned over for a skiving operation on its oppositeedge.

Although a preferred embodiment of this invention is illustrated, it isto be understood that various modifica- 4 tions and rearrangements ofparts may be resorted to without departing from the scope of theinvention.

I claim:

1. Apparatus for skiving edge portions of sheet stock, comprising a flattable having a surface adapted to support sheet stock, said table havingmeans to retain an edge of said stock in coplanar relationship with anedge of said table, an endless abrasive belt mounted between a driveroller and an idler roller and having a flat reach extending at an acuteangle with respect to the plane of said table, at least a portion ofsaid flat reach overlying and being intersected by a plane normal tosaid table and passing through said table edge, one of said rollershaving at least a portion thereof located below the plane of said table,said roller adjacent said portion of said flat reach being supportedrelative to the table by a roller which is adapted to roll along a shelfportion of said table adjacent said edge.

2. Apparatus according to claim 1, wherein said supporting roller has afirst portion of relatively small diameter and an axially adjacentportion of relatively large diameter.

3. Apparatus according to claim 2, including means to axially shift theposition of said supporting roller toward and away from the table sothat said large and small diameter portions may selectively roll alongsaid shelf to change the depth of cut by said belt.

4. Apparatus for skiving edge portions of sheet stock, comprising a fiattable having a surface adapted to support sheet stock, said table havingmeans to retain an edge of said stock in coplanar relationship with anedge of said table, an endless abrasive belt mounted between a driveroller and an idler roller and having a flat reach extending at an acuteangle with respect to the plane of said table, at least a portion ofsaid flat reach overlying and being intersected by a plane normal tosaid table and passing through said table edge, said drive roller beingrotatably mounted on a bracket having a hub portion, a guide rod passingthrough said hub portion and being parallel to the edge of said table, athreaded shaft rotatably mounted on said table, means for rotating saidthreaded shaft, means fixed to said hub portion and engaging the threadsof said shaft, a beam extending from said hub portion and having itsdistal end fixed to a support arm, said idler roller being rotatablymounted on said support arm and having a portion thereof located belowthe plane of .said table.

1. Apparatus for skiving edge portions of sheet stock, comprising a flattable having a surface adapted to support sheet stock, said table havingmeans to retain an edge of said stock in coplanar relationship with anedge of said table, an endless abrasive belt mounted between a driveroller and an idler roller and having a flat reach extending at an acuteangle with respect to the plane of said table, at least a portion ofsaid flat reach overlying and being intersected by a plane normal tosaid table and passing through said table edge, one of said rollershaving at least a portion thereof located below the plane of said table,said roller adjacent said portion of said flat reach being supportedrelative to the table by a roller which is adapted to roll along a shelfportion of said table adjacent said edge.
 2. Apparatus according toclaim 1, wherein said supporting roller has a first portion ofrelatively small diameter and an axially adjacent portion of relativelylarge diameter.
 3. Apparatus according to claim 2, including means toaxially shift the position of said supporting roller toward and awayfrom the table so that said large and small diameter portions mayselectively roll along said shelf to change the depth of cut by saidbelt.
 4. Apparatus for skiving edge portions of sheet stock, comprisinga flat table havIng a surface adapted to support sheet stock, said tablehaving means to retain an edge of said stock in coplanar relationshipwith an edge of said table, an endless abrasive belt mounted between adrive roller and an idler roller and having a flat reach extending at anacute angle with respect to the plane of said table, at least a portionof said flat reach overlying and being intersected by a plane normal tosaid table and passing through said table edge, said drive roller beingrotatably mounted on a bracket having a hub portion, a guide rod passingthrough said hub portion and being parallel to the edge of said table, athreaded shaft rotatably mounted on said table, means for rotating saidthreaded shaft, means fixed to said hub portion and engaging the threadsof said shaft, a beam extending from said hub portion and having itsdistal end fixed to a support arm, said idler roller being rotatablymounted on said support arm and having a portion thereof located belowthe plane of said table.